49ers sign defensive back Dexter McCoil

The 49ers placed safety Terrell Williams Jr. on injured reserve with a leg injury Friday to make room on the roster.

McCoil originally joined the 49ers last season after the team claimed him off waivers from the Chargers in October. He played in eight games for San Francisco and registered one tackle. McCoil was waived on April 30.

Williams originally signed with the 49ers as an undrafted rookie free agent out of Houston. He got injured during joint practices this week.